CLEANLINESS EVALUATING METHOD FOR METAL MATERIAL

摘要

PROBLEM TO BE SOLVED: To provided a quick and precision cleanliness evaluating method for a metal material which corresponds to mass production process for the metal material as well. SOLUTION: The cleanliness of the metal material is evaluated by acquiring a maximum diameter of an intervening oxide substance. N-pieces of samples are taken out of the metal material which is to be analyzed. A spark discharge is performed a plurality of times between a sample piece and a pair electrodes for each sample piece, to detect a maximum luminous spectrum intensity caused by intervening oxide substances in the sample piece. Based on an analytical curve where the maximum luminous spectrum intensity corresponds to the maximum diameter of the oxide intervening substance, a maximum diameter aj of an intervening oxide substance is calculated for n-pieces of samples, to evaluate cleanliness of the metal material to be analyzed.